For some time, various companies and persons have worked to improve the performance and reduce the adverse environmental effects of internal combustion engines. As the increased use of automobiles in the United States has offset reductions in auto emissions, legislators, regulators, the petroleum and automobile industries and various other groups have sought new ways to address air pollution from cars. As part of that effort, these groups have increasingly focused on modification of fuels and fuel additives. Perhaps the best known fuel modification relating to air pollution control is the elimination of lead, used as an antiknock compound, from gasoline.
The 1990 amendments to the Clean Air Act contain a new fuels program, including a reformulated gasoline program to reduce emissions of toxic air pollutants and emissions that cause summer ozone pollution, and an oxygenated gasoline program to reduce carbon monoxide emissions in areas where carbon monoxide is a problem in winter. Environmental agencies, such as the United States Environmental Protection Agency (EPA) and the California Air Resources Board (CARB), have promulgated various regulations compelling many fuel modification efforts. A coalition of automobile manufacturers and oil companies has extensively reviewed the technology for improving fuel formulations and produced what has been referred to as the "Auto/Oil" study. The data from the Auto/Oil study has formed the basis for some regulatory approaches, such as CARB's matrix of acceptable gasoline formulations.
With respect to the oxygenated gasoline program, the most commonly used oxygenates are ethanol, made from biomass (usually grain or corn in the United States) and methyl tertiary butyl ether (MTBE), made from methanol that is usually made from natural gas. Oxygenates such as ethanol and MTBE increase a fuel's octane rating, a measure of its tendency to resist engine knock. In addition, MTBE mixes well with gasoline and is easily transported through the existing gasoline pipeline distribution network. See, American Petroleum Institute website: Issues and Research Papers (http://www.api.org/newsroom.cgi) "Questions About Ethanol" and "MTBE Questions and Answers"; and "Achieving Clean Air and Water: The Report of the Blue Ribbon Panel on Oxygenates in Gasoline," which are incorporated herein by reference.
Reformulated gasoline has been blended to reduce both exhaust and evaporative air pollution, and to reduce the photochemical reactivity of the emissions that are produced. Reformulated gasoline is certified by the Administrator of the EPA and must include at least two percent (2%) oxygenate by weight (the so-called "oxygen mandate"). Ethanol and MTBE are both used in making reformulated gasoline.
Both ethanol (as well as other alcohol-based fuels) and MTBE have significant drawbacks. Ethanol-based fuel formulations have failed to deliver the desired combination of increased performance, reduced emissions, and environmental safety. They do not perform substantially better than straight-run gasoline and increase the cost of the fuel.
Adding either ethanol or MTBE to gasoline dilutes the energy content of the fuel. Ethanol has a lower energy content than MTBE, which in turn has a lower energy content than straight-run gasoline. Ethanol has only about 67% the energy content of the same volume of gasoline and it has only about 81% of the energy content of an equivalent volume of MTBE. Thus, more fuel is required to travel the same distance, resulting in higher fuel costs and lower fuel economy. In addition, the volatility of the gasoline that is added to an ethanol/gasoline blend must be further reduced in order to offset the increased volatility of the alcohol in the blend.
Ethanol has not proven cost effective, and is subject to restricted supply. Because of supply limitations, distribution problems, and its dependence on agricultural conditions, ethanol is expensive. The American Petroleum Institute reports that, in 1999, ethanol was about twice the cost of an energy equivalent amount of gasoline. The politics of agriculture also effect ethanol supply and price.
Ethanol also has a much greater affinity for water than do petroleum products. It cannot be shipped in petroleum pipelines, which invariably contain residual amounts of water. Instead, ethanol is typically transported by truck, or manufactured where gasoline is made. Ethanol is also corrosive In addition, at higher concentrations, the engine must be modified to use an ethanol blend.
Ethanol has other drawbacks as well. Ethanol has a high vapor pressure relative to straight-run gasoline. Its high vapor pressure increases fuel evaporation at temperatures above 130.degree. Fahrenheit, which leads to increases in volatile organic compound (VOC) emissions. EPA has concluded that VOC emissions would increase significantly with ethanol blends. See, Reformulated Gasoline Final Rule, 59 Fed. Reg. 7716, 7719 (1994).
Finally, although much research has focused on the health effects of ethanol as a beverage, little research has addressed ethanol's use as a fuel additive. Nor has ethanol been evaluated fully from the standpoint of its environmental fate and exposure potential.
MTBE has its share of drawbacks as well. MTBE was first added to gasoline to boost the octane rating. In line with the 1990 Clean Air Act amendments, MTBE was added in even larger amounts as an oxygenate to reduce air pollution. Unfortunately, MTBE is now showing up as a contaminant in groundwater throughout the United States as a result of releases (i.e., leaking underground gasoline storage tanks, accidental spillage, leakage in transport, automobile accidents resulting in fuel releases, etc.).
MTBE is particularly problematic as a groundwater contaminant because it is soluble in water. It is highly mobile, does not cling to soil particles, and does not decay readily. MTBE has been used as an octane enhancer for about twenty years. The environmental and health risks posed by MTBE, therefore, parallel those of gasoline. Some sources estimate that 65% of all leaking underground fuel storage tank sites involve releases of MTBE. It is estimated that MTBE may be contaminating as many as 9,000 community water supplies in 31 states. A University of California study showed that MTBE has affected at least 10,000 groundwater sites in the State of California alone. The full extent of the problem may not be known for another ten years. See, "MTBE, to What Extent Will Past Releases Contaminate Community Water Supply Wells?," ENVIRONMENTAL SCIENCE AND TECHNOLOGY, at 2-9 (May 1, 2000), which is incorporated herein by reference.
EPA also has determined that MTBE is carcinogenic, at least when inhaled. Other unwelcome environmental characteristics are its foul smell and taste, even at very low concentrations (parts per billion). Because of the se drawbacks, the U.S. government is considering banning MTBE as a gasoline additive. In September 1999, EPA recommended that MTBE use be curtailed or phased out. Several states are planning to halt or reduce MTBE use. California plans to phase it out by 2002, and Maine already has the EPA's permission to quit using MTBE if it can find other ways of meeting air quality standards. The EPA also has approved New Jersey's request to stop using MTBE in gasoline during the winter.
The environmental threat from MTBE may be even greater than that from an equivalent volume of straight-run gasoline. The constituents of gasoline considered most dangerous are the aromatic hydrocarbons: benzene, toluene, ethylbenzene, and xylene (collectively, "BTEX"). The BTEX aromatic hydrocarbons have the lowest acceptable drinking water contamination limits. Both ethanol and MTBE enhance the environmental risks posed by the BTEX compounds, apart from, their own toxicity. Ethanol and MTBE act as a co-solvent for BTEX compounds in gasoline. As a result, the BTEX plume from a source of gasoline contamination containing ethanol and/or MTBE travels farther and faster than one that does not contain either oxygenate.
The BTEX aromatic compounds have relatively lower solubility in water than MTBE. BTEX compounds tend to biodegrade in situ when they leak into the soil and ground water. This provides at least some natural attenuation. Relative to the BTEX compounds, however, MTBE biodegrades at a significantly lower rate, by at least one order of magnitude, or ten times more slowly. Some sources estimate that the time required for MTBE to degrade to less than a few percent of the original contaminant level is about ten years.
Other initiatives have involved efforts to formulate a cleaner burning--reformulated--gasoline. For example, Union Oil Company of California (UNOCAL) has secured a number of U.S. patents that cover various formulations of RFG. Jessup, et al., U.S. Pat. No. 5,288,393, for Gasoline Fuel (Feb. 22, 1994); Jessup, et al., U.S. Pat. No.5,593,567, for Gasoline Fuel (Jan. 14, 1997); Jessup, et al., U.S. Pat. No. 5,653,866, for Gasoline Fuel (Aug. 5, 1997); Jessup, et al., U.S. Pat. No. 5,837,126 for Gasoline Fuel, (Nov. 17, 1998); Jessup, et al., U.S. Pat. No. 6,030,521 for Gasoline Fuel (Feb. 29, 2000). The UNOCAL patents specify various end points in the blending of gasoline, and purport to reduce emissions of selected contaminants: Carbon monoxide (CO); Nitrous oxides (NOx); Unburned Hydrocarbons (HC); and other emissions.
UNOCAL has already enforced one of its RFG patents. Union Oil Company of California v. Atlantic Richfield, et al., 34 F.Supp.2d 1208 (C.D. Cal. 1998); and Union Oil Company of California v. Atlantic Richfield, et al., 34 F.Supp.2d 1222 (C.D. Cal. 1998). The District Court judgment established a substantial royalty rate (53/4 cents per gallon) for UNOCAL's patented RFG formulation. This has increased substantially the cost of motor fuels in the affected markets. Although the judgment has been affirmed on appeal, Union Oil Company of California v. Atlantic Richfield, et al., 208 F.3d 989,54 USPQ2d 1227 (Fed. Cir. 2000), review by the Supreme Court is currently being sought.
Historically, margins in the refining and marketing of motor fuels tend to be narrow, typically less than cents a gallon. Alexi Barrionuevo, "Stumped at the Pump? Look Deep into the Refinery," WALL STREET JOURNAL, B1 (May 26, 2000), which is incorporated herein by reference. RFG imposes added costs on refiners. These formulations increase the cost of the finished product, relative to straight-run gasoline. Memorandum from Lawrence Kumins, Specialist in Energy Policy, Resources, Science and Industry Division, Library of Congress, to Members of Congress, "Midwest Gasoline Price Increases (Jun. 16, 2000), which is incorporated herein by reference. UNOCAL's royalty rate of 53/4 cents per gallon imposes a substantial additional cost burden on RFG.
These various problems have impaired the efficacy or cost-effectiveness of each of these various alternatives. Alcohols have not resolved the performance and emission needs for improved motor fuels. MTBE imposes unacceptable environmental (soil and groundwater) and public health problems. Methyl Tertiary Butyl Ether (MTBE), 65 Fed.Reg. 16093 (2000) (to be codified at 40 C.F.R. pt. 755) (proposed Mar. 24, 2000). Reformulated gasoline has been controversial and expensive. Accordingly, there remains a substantial and unmet need for an improved gasoline formulation that enhances (or at least does not impair) performance, while reducing emissions and the environmental and public health risks from motor fuels. The present invention satisfies those needs.
The present invention employs a unique combination of nitroparaffins and ester oil and/or toluene, to enhance the performance of and reduce emissions from internal combustion engines and, in particular, automobiles. Nitroparaffins have been used in prior fuel formulations, for different engine applications, without achieving the results of the present invention. For example, nitroparaffins have long been used as fuels and/or fuel additives in model engines, turbine engines, and other specialized engines. Nitromethanes and nitroethanes have been used by hobbyists. Nitroparaffins have also been used extensively in drag racing, and other racing applications, due to their extremely high energy content.
The use of nitroparaffins in motor fuels for automobiles, however, has several distinct disadvantages. First, some nitroparaffins are explosive and pose substantial hazards. Second, nitroparaffins are significantly more expensive than gasoline--so expensive as to preclude their use in automotive applications. Third, nitroparaffins have generally been used in specialized engines that are very different than automotive engines. Fourth, the high energy content of nitroparaffins requires modification of the engine, and additional care in transport, storage, and handling of both the nitroparaffin and the fuel. Further, in some fuel applications, nitroparaffins have had a tendency to gel. The high cost, and extremely high energy content of nitroparaffins, has precluded their use as an automotive fuel. Moreover, the extreme volatility and danger of explosion from nitromethane taught away from its use as a motor fuel for automobiles.
Notwithstanding these drawbacks, patents have been issued for fuel formulations containing nitroparaffins. One of these, Michaels, U.S. Pat. No. 3,900,297 for Fuel for Engines (Aug. 19, 1975), describes a fuel formulation for engines comprising nitroparaffin compositions. Michaels notes that nitroparaffin formulations have a tendency to pre-ignition in reciprocating internal combustion engines. Moreover, Michaels notes that nitroparaffins are not readily miscible in hydrocarbons.
Michaels discloses and claims a formulation that is intended to increase the solubility of nitroparaffins in hydrocarbons. Michaels claims that nitroparaffins can be made soluble in gasoline by including a synthetic ester lubricating oil. Michaels specifies that any commercially available gasoline, having a boiling point between 140.degree. to 400.degree. F. is suitable. Michaels asserts that the inclusion of ester lubricating oil at the levels specified by Michaels "would render perfectly miscible otherwise immiscible nitroalkane/gasoline blends." Michaels '297 patent, at Col. 2, ll. 27-28.
Michaels expressly notes that one of the advantages of including ester lubricating oil in his invention is to provide upper cylinder lubrication: "[i]nclusion of ester lubricant in fuel compositions for reciprocating combustion engines has the further advantage of providing internal lubrication within the engine, thereby reducing engine wear and improving engine efficiency." Michaels, '297 patent at Col. 2, ll. 31-35. "Ester lubricants of the type suitable for use in the fuel compositions of the present [Michaels'] invention include those which have found wide use as "synthetic oil" in modern jet engines. These include the commercially available synthetic lubricating oils metting [sic] Military Specifications MIL-L-7808 and MIL-L-9236 of the ester type. Specific examples of commercially available synthetic oils suitable for use in the compositions of the present invention include Texaco SATO No. 7730 Synthetic Aircraft Turbine Oil, Monsanto Skylube No. 450 Jet 20 Engine Oil, and [Mobil] II Turbine Oil." Michaels '297 patent, at Col. 3, ll. 11-21. Michaels describes the chemical formulations of various ester oils, Michaels '297 patent, at Col. 3, ll. 11 to Col. 6, ll. 42, which discussion is incorporated herein by reference. The ester lubricating oils of the present invention include, without limitation, those described by Michaels in his '297 patent as well as any other ester oils that may be suitable to achieve the objects of the present invention.
Michaels expressly notes that: "[c]ommercially available ester oils of the above description usually contain additives to improve their performance as lubricants, which additives do not ordinarily adversely affect performance of such oils in my [Michaels'] fuel compositions. In general, for reasons of ready availability, use of ester oil in the form of commercially available synthetic ester turbine oils is preferred." Michaels '297 patent, at Col. 4, ll. 44-50. Michaels not only includes the additives normally found commercially in such ester oils, he expressly prefers them.
Among those additives typically included in commercially available ester oils are flame retardants. These flame retardants inhibit the combustion of the oil, without impairing the miscibility of the nitroparaffins, allowing the ester oil to lubricate the upper cylinder.
Michaels specifies that: "[t]he ester oil is preferably employed in minimum amount required to provide a homogeneous liquid fuel compositions [sic]. Use of less than that amount results in non-homogeneous compositions, with concomitant physical separation of liquid components into layers, and use of excess amounts of ester oil is wasteful and may result in excess carbon deposition within the engine, fouling of sparkplugs and generally unsatisfactory engine operation. No general rule can be set down fixing precise amounts of ester oil required to achieve homogeneity of the compositions, since that amount depends on variables such as the type of gasoline, nitroalkane and ester oil, as well as the proportions in which gasoline and nitroalkane are incorporated into the composition . . . As a general guide, use of ester oil in proportions of from 1 to 4 parts of ester oil to 8 parts of nitroalkane will ordinarily provide a homogeneous blend." Michaels '297 patent, at Col. 5, ll. 47 to Col. 6, ll. 2.
Michaels' only disclosure of making the additive or fuel relates to how to determine the appropriate amount of ester oil to provide a homogeneous blend: "the required amounts of ester oil are readily determined by simple experimentation of a routine nature, e.g. by first adding the nitroalkane to the gasoline in desired amount, then adding the ester oil in small portions, followed by thorough mixing after each addition until a homogeneous blend is obtained." Michaels, '297 patent, at Col. 5, ll. 61-66. In contrast, both the process of the present invention and the product obtained by the present process, are different than Michaels.
Michaels claims that his invention improves combustion efficiency: "[t]he advantages of using the fuel of the present invention are found in lower fuel consumption due to high BTU of energy developed resulting in higher horsepower output and cleaner burning, since the added blends (of nitroalkanes and their mixtures) improve combustion efficiency," Michaels '297 patent at Col. 5 6, ll. 29-34, in conjunction with glow plug engines. Michaels speculates that "[t]he same advantages may occur when this fuel is used in other internal combustion engines or jet engines." Michaels '297 patent, at Col. 6, ll. 34-36. Yet, Michaels provides no data to support this conjecture. Nor does Michaels identify any increase in horsepower or reduction in emissions, apart from high BTU content and higher fuel efficiency of Michaels' fuel.
Michaels claims a fuel comprising from 5 to 95% (volume) gasoline and 95% to 5% additive. Michaels' additive, in turn, comprises from 10 to 90% nitroparaffin and 90 to 10% ester lubricating oil. Michaels claims that his fuel is a homogeneous blend of additive and gasoline. He attributes his results to the ability of the ester lubricating oil to make the nitroparaffin soluble in gasoline. Michaels' components are a blend and do not react with one another. They are a simple mixture.
The present inventors are not aware that the formulation described and claimed by Michaels has ever been used as a motor fuel for automobiles. Although Michaels sold a fuel additive for automobiles, the present inventors believe that the additive Michaels sold may have been different than the additive disclosed in Michaels' '297 patent.
Michaels' fuel comprises 0.5 to 81.5 volume percent nitroalkane. At levels this high, Michaels' formulation teaches strongly away from automotive applications. The energy content of the nitroalkanes is simply too high for automotive use. Michaels himself provided examples of only model engines, turbine, jet engine, and other specialized applications. Nor would Michaels have been understood by persons of ordinary skill in the art as suggesting a viable automotive fuel. High nitroalkane levels would likely damage or destroy an automotive engine.
The cost of Michaels' additive is substantially higher than the cost of gasoline. At a concentration of even 5 volume percent, the cost of the finished formulation blended according to Michaels' teachings would be multiples, if not orders of magnitude, higher than the cost of an equivalent volume of gasoline. At higher concentrations, which Michaels teaches may range up to 95 volume percent, the cost is prohibitive. Michaels' fuel is not cost-effective for motor vehicle use.
Prior to 1985, a similar composition was marketed by an individual named Moshe Tal, through a corporation named TK-7. Mr. Tal sold the formulation as "ULX-15." From 1985 to March of 1987, Tal supplied a formulation that reportedly was made in accordance with the '297 patent, to a company trading under the name Energex. Energex actively marketed the product throughout the western United States by advertising it in "outdoor" magazines such as FIELD AND STREAM. Energex principals attended various events, such as fishing competitions, where on at least one occasion they demonstrated the Energex/TK-7 product for use in fishing boat engines. The Energex/TK-7 formulation enjoyed limited sales only in a narrow, non-automotive market. Michaels later asserted that the Energex/TK-7 formulation was covered by his '297 patent.
The present inventors believe that the Energex/TK-7 formulation comprised the following composition:
TABLE 1 "Energex/TK-7" Formulation Volume of Formulation Component (Parts of Total) Nitropropane 2 35-38 Nitroethane 3-4 Nitromethane 1-2 Mobil Jet II .TM. 1/2-1 Alcohol (methanol or isopropyl) 1-2 Total: 401/2-47
In 1986, an individual identifying himself as Michaels contacted Energex, and claimed that Energex's additive infringed Michaels' '297 patent. A principal of Energex, Don Young, met with Michaels in NewYork in 1986. Young observed some portions of Michaels' preparation of the '297 additive. Although no mixing process is disclosed in the '297 patent, Young understood that the preparation of the '297 composition involved a specific mixing procedure. Energex and Michaels entered into an agreement whereby Energex continued to sell the formulation.
The present inventors believe that the Energex/TK-7 additive was sold for both gasoline and diesel-fueled outboard motor engines. One or two gallons of diesel fuel was added to the diesel formulation. The present inventors are unaware of any performance testing of the Michaels formulation from this time period (prior to March 1987). In 1987, Energex ran out of money, declared bankruptcy, and stopped selling. The TK-7 product was not marketed from March of 1987 until about May of 1988.
In May of 1988, Young began selling the product in a slightly modified form, under the name "PbFree." PbFree secured product from W. R. Grace, under Michaels' supervision. PbFree sold the formulation as "TGS." The TGS formulation of the additive as sold by PbFree was substantially the same as the Energex/TK-7 formulation:
TABLE 2 PbFree "TGS" Formulation (1988 to 1990) Volume of Formulation Component (Parts of Total) Nitropropane 2 35-38 Nitroethane 3-4 Nitromethane 1-2 Mobil Jet II .TM. 1/2-1 Alcohol (methanol or isopropyl) 1-2 Total: 401/2-47
Although the present inventors are aware of no performance data available for the Energex/TK-7 formulation that was apparently sold from prior to 1985 through 1987, performance testing was conducted on the PbFree TGS formulation between 1989 and 1990.
As a general proposition, motor fuel testing is subject to a high degree of variability, requiring precisely defined test parameters and controls. Gasoline is extremely variable in composition. Control of the fuel is essential to securing statistically significant results from engine performance testing. Annual Book of ASTM Standards 2000, Section Five: Petroleum Products, Lubricants, and Fossil Fuels, Volume 05.04, Petroleum Products and Lubricants (IV): D 5966-latest; American National Standards Institute (ANSI), "Automotive Fuels--Diesel--Requirement and Test Methods", Publication No. SS-EN 590, and "Automotive Fuels--Unleaded petrol--Requirements and Test Methods," Publication No. SS-EN 228; Society of Automotive Engineers (SAE), "Automotive Gasolines," Publication No. J312.sub.-- 199807 (July 1998), which are incorporated herein by reference.
The variability of different runs of the same formulation under comparable conditions may vary by as much as 5-17%, depending on the emission variable being measured. Variability is also inherent in the data collected in performance testing. Vehicles differ and even the same vehicle varies in performance from day to day. The variability between "nominally identical cars" can be from approximately 10 to 27 percent of the mean value, for a repeated number of tests using the same fuel in a number of similar vehicles. The Effects of Aromatics, MTBE, Olefins and T.sub.90 on Mass Exhaust Emissions from Current and Older Vehicles--The Auto/Oil Quality Improvement Research Program. Society of Automobile Engineers (SAE) Technical Paper Series 912322, International Fuels and Lubricants Meeting and Exposition, Toronto, Canada (Oct. 7-10, 1991), which is incorporated herein by reference. In repeated testing of the same vehicles using the same fuel, results may vary from approximately 5 to 17% of the mean value (SAE, 1991). Atmospheric conditions, such as humidity, may also introduce variability. (SAE, 1991).
The testing of the TGS product between 1989 and 1990 did not satisfy even these generally accepted requirements for reliability in engine performance testing. Accordingly, the variability of the TGS test data is expected to be even higher than 5-17%.
Preliminary testing of the TGS product was conducted by the University of Nebraska and Cleveland State University in 1989 and 1990. Both were small "pilot" studies. Both researchers recommended more aggressive tests to validate the initial results. The present inventors believe that such definitive testing was never conducted.
Professor Ronald Haybron of the Department of Physics of the Cleveland State University conducted a preliminary evaluation of the TGS product in 1989. He tested one vehicle and used regular (87 octane) unleaded pump gasoline, rather than a standard fuel formulation, as required by generally accepted testing standards. Nor were data measured at the same points (for example, at the same engine speeds). These limitations of procedure, small sample size, and lack of adequate control preclude any reliable conclusions being drawn from the Cleveland State study.
The Cleveland State study tested the additive at a concentration of 0.1 oz. of additive per gallon of fuel. This is a concentration of additive well below the levels specified and claimed in Michaels' '297 patent. Michaels discloses an additive concentration of 5 to 95% (6.25 oz. to 121.6 oz. per gallon) or more. The Cleveland State test was run outside that range. Although the results were not statistically significant, Prof. Haybron claimed an improvement in horsepower of 8 to 20%, and reduced carbon monoxide output of 8 to 10%, well within the variability of even a well-controlled study.
Professor Peter Jenkins, of the University of Nebraska, failed to replicate these results. The University of Nebraska, Mechanical Engineering Department conducted testing on the "TGS Fuel Additive." The Nebraska testing evaluated the data at the same engine speeds for each concentration, of additive. However, pump gas (regular 87 octane) was also used instead of a controlled, reference fuel. Only two vehicles were tested. Although some evaluations showed improvement at higher concentrations of additive (i.e., at 0.5 oz. per gallon), they showed little, if any, difference at the lowest concentrations tested (0.1 oz. per gallon). Although Prof. Jenkins claimed that the testing showed a 10 to 14% improvement in fuel consumption, those values are well within the variability of even a well-controlled study. There was little to no improvement on other parameters.
In 1990, PbFree modified the formulation but continued selling the additive having the composition identified in Table 3:
TABLE 3 PbFree Formulation (1990 to 1998) Volume of Formulation Component (Parts of Total) Nitropropane 2 28 Nitroethane 11-15 Nitromethane 6-15 Mobil Jet II .TM. 1 Total: 46-59
The present inventors believe that PbFree attempted to sell the product to Leaseway Trucking Company and the Cummins Engines Corporation during 1991. At that time, the formulation was supplied by W. R. Grace under Michaels' supervision.
The present inventors believe that PbFree supplied the product to the Brigham Young University (BYU), School of Engineering for testing. The product was provided by Michaels. The present inventors understand that the PbFree composition failed, namely, that the PbFree (Michaels) formulation failed to improve performance or reduce emissions in the BYU tests.
In 1992, Michaels stopped supplying product to PbFree. Young attempted to replicate Michaels' formulation from publicly available sources, such as Michaels '297 patent. Young was unable to replicate Michaels' formulation from the '297 patent alone, yet, based upon Young's observation of Michaels preparing his additive in 1986, Young determined that a special mixing step was necessary. Young experimented with various methods--stirring, rolling the components in a closed barrel, and "thermoaeration"--and was able to offer an additive formulation for sale. None of these mixing procedures are disclosed in Michaels' '297 patent.
Young continued making and selling the formulation identified above as the "PbFree" formulation, until 1998, at which point PbFree ceased operations. The present inventors are aware of no testing regarding the performance of the PbFree formulation during this period. In 1998, Young began selling the additive under the name Envirochem, LLC ("Envirochem"). The Envirochem "EChem" formulation is identified in Table 4:
TABLE 4 Envirochem "EChem" Formulation (1998 to 1999) Volume of Formulation Component (Parts of Total) Nitropropane (1 or 2) 29 Nitroethane 10 Nitromethane 10 Toluene 5 Mobil Jet II .TM. 1 Total: 55
In addition to the prior formulations derived from Michaels (namely, the ULX-15, TGS, PbFree, and EChem formulation discussed above), other inventors have disclosed and claimed additives comprising nitroparaffins and either toluene and/or ester oil. Many of these prior known formulations, however, were either for use as a model engine fuel or lubricant. See e.g., Brodhacker, U.S. Pat. No. 2,673,793 for Model Engine Fuel (Mar. 30, 1954); Hartley, U.S. Pat. No. 5,880,075 for Synthetic Biodegradable Lubricants and Functional Fluids (Mar. 9, 1999); and Tiffany, U.S. Pat. No. 5,942,474 for Two-Cycle Ester Based Synthetic Lubricating Oil (Aug. 24, 1999). Two patents of which the present inventors are aware disclose the use of a nitroparaffin and ester oil/toluene formulation for use as a fuel additive: Gorman, U.S. Pat. No. 4,330,304 for Fuel Additive (May 18, 1982); and Simmons, U.S. Pat. No. 4,073,626 for Hydrocarbon Fuel Additivie and Process of Improving Hydrocarbon Fuel Combustion (Feb. 14, 1978).
Gorman discloses a mixture of nitroparaffins, including: nitropropane, nitroethane, nitromethane, and others, at 3-65 weight percent of the additive. Gorman also discloses formulations in which toluene is present at a concentration of 74 weight percent, well in excess of the present invention, along with propylene oxide, tert-butyl hydroperoxide, nitropropanes 1 and 2, and acetic anhydride. Gorman, '304 Patent, Col. 9, ll. 53.
Simmons discloses a mixture of one part iron salts of aromatic nitro acid, 10 to 100 parts nitroparaffin, and a solvent, which may be toluene. Simmons does not disclose the use of ester oil. In some of Simmons' examples the salt is added directcly to the fuel with no solvent. In at least two of Simmons' examples, the solvent comprises about a quarter of the fuel blend, well in excess of the concentrations of toluene and/or ester oil in the present invention.
Neither Gormnan nor Simmons, nor any of the other known prior formulations, disclose the ranges of nitroparaffins, and ester oil and/or toluene of the present invention, let alone the unique benefits of the present invention to reduce emissions. Prior known formulations were made by a different process than the present invention. Many of the prior known formulations are used at higher concentrations in the fuel than is the present invention. The present invention, however, reduces emissions at lower concentrations of additive. In addition, the present invention may be used with a variety of fuels, including: gasoline, gasoline and MTBE, gasoline and ethanol, and gasoline/ethanol/MTBE formulations.
In January 2000, Envirochem's assets were purchased by First Stanford Envirochem, Inc., trading as Magnum Environmental Technologies, Inc., the assignee of the present application. The present inventors have made a diligent effort to study and improve upon the prior known formulations. As a result of these efforts, the present applicants have invented a new formulation, and method of producing and using the same.
The present inventors began by investigating the EChem formulation. A study conducted by Emission Testing Service (ETS) in January 2000 found that, although the EChem formulation performed comparable to or slightly worse than both a standard unleaded gasoline and standard gasoline plus 11% MTBE, it reduced carbon monoxide emissions relative to gasoline, reduced NOx emissions relative to gasoline plus MTBE, and improved fuel efficiency relative to both.
The present invention differs in significant respects from the prior known formulations, as well as from alcohol-based (ethanol) and MTBE fuel additives, and performs better than prior known formulations. One embodiment of the present invention is disclosed in Table 5:
TABLE 5 "MAZ 100" Formulation Volume of Formulation Component (Parts of Total) Nitropropane 1 29 Nitroethane 10 Nitromethane 10 Toluene 5 Modified Ester Oil Lubricant 1 Total: 55
The present inventors have made a number of specific changes in the formulation and in the method of preparing the composition of the present invention. The present inventors believe that these changes produce the improvements they have observed.
Although prior formulations used nitropropane 2, or a combination of nitropropane and 2, the present inventors preferably remove nitropropane 2 from the formulation. Nitropropane 2 is a known carcinogen. Its removal improves the material handling safety of the product.
Unlike the prior known formulations, which employed commercially available ester oils, the present inventors preferably modify the ester oil to remove, or not to introduce, tricresyl phosphate. Tricresyl phosphate is a known neurotoxin. In addition, tricresyl phosphate has flame retardant properties. The present inventors believe that this modification allows improved performance of the invention in terms of reduced emissions, at lower concentrations of additive, particularly on cold start up. It also makes the product safer to handle.
The present inventors preferably add toluene to the formulation. The inventors believe that toluene may emulsify the nitroparaffins into, or make the nitroparaffins more soluble in, gasoline and lower emissions.
The present inventors preferably lower the amount of ester oil to levels below most of the known prior additives. This too has been found to lower emissions.
The present inventors preferably lower the concentration of nitromethane. Nitromethane is also a known neurotoxin. Reduction of nitromethane reduces toxicity and lowers emissions.
The present invention is preferably employed at a lower overall concentration in the fuel relative to most prior known formulations. This too lowers emissions and reduces toxicity.
The present invention improves performance, reduces material handling requirements, and lowers environmental and public health and safety risks, as well as emissions, at concentrations at which prior formulations were either untested, ineffective, or failed to produce the unique combination of benefits of the present invention.
It has not been reliably established that the prior known formulations provided any improvement in performance or emissions. The present invention, on the other hand, achieves benefits, at low concentrations of additive. Thus, the present invention meets the long-felt, yet unresolved, need for an environmentally safe, improved fuel additive. None of the prior formulations of which the present inventors are aware reduce emissions, particularly on cold start-up. None of the prior known formulations suggest the present invention.